I didn't think about humidifiers this way. I'm VERY susceptible to sinus infections and prone to sinus drainage in the winter with the heater running. Until I started regularly running a humidifier at night, I was getting numerous infections due to sinus drainage in a year. (Sinus drainage for me also leads to ear infections as well.)

This is also another reason I REFUSE to wear a mask, bacteria build up leading to sinus infections. No thanks.